Spinal surgeons frequently must work with openings within the body known as “foramina.” It may be difficult to visualize or to evaluate the size or diameter of these foramina, such as, for example, during surgery or if the foramen is very small. In this situation, locating, measuring, or evaluating the enlargement of the foramen can be very difficult. For example, the openings where nerves exit the side of the spine, called “neural foramina,” are frequently very narrow. The neural foramen can be particularly narrow in patients with a common condition known as “spinal stenosis,” where the spinal nerves are compressed by enlarged, arthritic facet joints. Inability to relieve this narrowing frequently will cause “failure” in back surgery, particularly when the surgery involves “decompression” or opening of the spinal canal and foramina to relieve the pressure on the spinal cord. In some patients, the neural foramen is so small that the surgeon must search to find it before attempting to enlarge it. When found, the surgeon resects pieces of the bone surrounding the foramen with surgical instruments, such as, for example, “Kerrison” ronguers, until he or she believes that the foramen has been adequately enlarged around the exiting nerve. This uncertainty about when the foramen is adequately enlarged frequently results in the surgeon overestimating the size of the foramen and discontinuing the enlargement prematurely. The greatest number of failures in spinal stenosis decompression surgeries occur because the surgeon has not adequately enlarged the foramen to provide adequate space for the exiting nerve.
Accordingly, a need exists for a system and method of finding and accurately evaluating the enlargement of foramina in patients undergoing surgery.